#motors

Tech Tips:

How does a typical single phase motor know how fast to run? Typical induction motors are dependent of the electrical cycle rate of the entering power (measured in hertz) for their speed. Our power in the US makes one complete rotation from positive electrical peak to positive peak 60 times per second or 60hz (50hz […]

Watts So Confusing?

Most motors are designed to a set amount of work, usually rated in either watts or horsepower (746 watts per HP). Watt's law states that watts = volts x amps. If a particular motor needs to do 1 horsepower of work at 120 volts, it will draw about 6.22 amps. And yes, in an inductive […]

HP, Motor HP, BHP, Motor Watts

Brake horsepower (BHP), motor nameplate HP, and the actual electrical power (watts) a motor will consume are different but related concepts. They can get confusing. So, we will tackle them one at a time. Let us start with simple definitions of work, power, and horsepower. Work = distance in feet x force in pounds, both […]

Motor Types

In residential and light commercial HVAC, we work primarily with PSC (permanent split capacitor) motors. However, it is good to be aware of some other types. PSC (Permanent Split Capacitor) A common medium torque single phase motor with a run capacitor always in the circuit. This type makes up the majority of HVAC motors (condenser […]

What Is Up With Blower Amps & Watts w/ Steve Rogers

Bryan Orr and Steve Rogers dive deep into measuring power consumption in HVAC blower motors, particularly focusing on the differences between PSC (Permanent Split Capacitor) and ECM (Electronically Commutated Motor) technologies. The discussion stems from a question raised at an educators' conference about the accuracy of clamp-on meters in measuring blower motor watt draw, […]

High Voltage A/C Electrical Class

This podcast is a high voltage A/C electrical class that Bryan gave to some of the Kalos apprentices. The high voltage journey begins with basic electrical theory. Basically, a difference in charge is needed for electrons to move and generate power. Motors, which are inductive loads, are the greatest users of power that we will […]

The Value of First Time Completion of PSC Motor Failures With Universal ECM

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In this short podcast, Bryan talks about evaporator coil placement based on a question submitted by a listener, John. Evap coil placement differs in furnace applications versus air handlers.

When we use air conditioners with furnaces, we usually put evaporator coils on the positive side to protect the heat exchanger from rusting out during the summer (due to condensation and the chemical reactions that can occur with the metal heat exchanger). However, when it comes to air handlers, they’re usually on the negative side. The coil is usually on the negative side of a fan coil or air handler because it keeps the blower motor cooler (though that doesn’t make a huge difference in terms of performance).

The HVAC system will lose fewer BTUs to leakage when the coil is on the negative side, which is better for energy efficiency; those BTUs can reach the conditioned space rather than the closet, garage, or wherever it is stored. Pulling air over the evaporator coil on the negative side, however, could potentially lead to greater turbulence.

We run into challenges with evap coil placement on gas furnaces when we have dual fuel systems (a heat pump and furnace working together). You can’t run gas heat over a heat pump coil due to the high head pressure, so a parallel setup would avoid the risks of high head pressure (downstream) or rusted-out heat exchangers (upstream).

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